Separator, secondary battery, and a method for manufacturing separator

Abstract

A secondary battery with little deterioration is provided. A secondary battery with high safety is provided. A separator having excellent characteristics is provided. A separator achieving the secondary battery with high safety is provided. A novel separator is provided. In the separator, a polymer porous film and a layer including a ceramic-based material containing a metal oxide microparticle are stacked, the thickness of the layer including a ceramic-based material is greater than or equal to 1 μm and less than or equal to 100 μm, and the film thickness of the polymer porous film is greater than or equal to 4 μm and less than or equal to 50 μm.

1 . A separator,
 wherein a polymer porous film and a layer comprising a ceramic-based material containing a metal oxide microparticle are stacked,   wherein a thickness of the layer comprising the ceramic-based material is greater than or equal to 1 μm and less than or equal to 100 μm, and   wherein a thickness of the polymer porous film is greater than or equal to 4 μm and less than or equal to 50 μm.   
     
     
         2 . The separator according to  claim 1 ,
 wherein a density of the layer comprising the ceramic-based material is greater than or equal to 0.1 g/cm 3  and less than or equal to 2 g/cm 3 .   
     
     
         3 . The separator according to  claim 1 ,
 wherein a porosity of the polymer porous film is higher than or equal to 20 volume % and lower than or equal to 90 volume %.   
     
     
         4 . The separator according to  claim 1 ,
 wherein a weight of the polymer porous film per unit area is greater than or equal to 4 g/m 2  and less than or equal to 20 g/m 2 .   
     
     
         5 . The separator according to  claim 1 ,
 wherein a weight of the polymer porous film per unit area is greater than or equal to 5 g/m 2  and less than or equal to 12 g/m 2 .   
     
     
         6 . The separator according to  claim 1 ,
 wherein the metal oxide microparticle comprises one or more of magnesium oxide, aluminum oxide, titanium oxide, silicon oxide, magnesium hydroxide, aluminum hydroxide, and titanium hydroxide.   
     
     
         7 . The separator according to  claim 1 ,
 wherein the metal oxide microparticle comprises magnesium hydroxide.   
     
     
         8 . The separator according to  claim 1 ,
 wherein an average particle diameter of the metal oxide microparticle is greater than or equal to 0.01 μm and less than or equal to 50 μm.   
     
     
         9 . The separator according to  claim 1 ,
 wherein the layer comprising the ceramic-based material is in contact with one surface of the polymer porous film.   
     
     
         10 . A separator,
 wherein a polymer porous film and a layer comprising a plurality of ceramic-based materials containing a metal oxide microparticle are stacked,   wherein the layer comprising the plurality of ceramic-based materials is positioned so that the polymer porous film is sandwiched therebetween,   wherein a thickness of the layer comprising the ceramic-based materials is greater than or equal to 1 μm and less than or equal to 100 μm, and   wherein a thickness of the polymer porous film is greater than or equal to 4 μm and less than or equal to 50 μm.   
     
     
         11 . The separator according to  claim 10 ,
 wherein a density of the layer comprising the ceramic-based materials is greater than or equal to 0.1 g/cm 3  and less than or equal to 2 g/cm 3 .   
     
     
         12 . The separator according to  claim 10 ,
 wherein a porosity of the polymer porous film is higher than or equal to 20 volume % and lower than or equal to 90 volume %.   
     
     
         13 . The separator according to  claim 10 ,
 wherein a weight of the polymer porous film per unit area is greater than or equal to 4 g/m 2  and less than or equal to 20 g/m 2 .   
     
     
         14 . The separator according to  claim 10 ,
 wherein a weight of the polymer porous film per unit area is greater than or equal to 5 g/m 2  and less than or equal to 12 g/m 2 .   
     
     
         15 . The separator according to  claim 10 ,
 wherein the metal oxide microparticle comprises one or more of magnesium oxide, aluminum oxide, titanium oxide, silicon oxide, magnesium hydroxide, aluminum hydroxide, and titanium hydroxide.   
     
     
         16 . The separator according to  claim 10 ,
 wherein the metal oxide microparticle comprises magnesium hydroxide.   
     
     
         17 . The separator according to  claim 10 ,
 wherein an average particle diameter of the metal oxide microparticle is greater than or equal to 0.01 μm and less than or equal to 50 μm.   
     
     
         18 . The separator according to  claim 10 ,
 wherein the layer comprising the ceramic-based material is in contact with one surface of the polymer porous film.   
     
     
         19 . A secondary battery, comprising:
 a positive electrode;   a negative electrode;   the separator according to  claim 1 , being sandwiched between the positive electrode and the negative electrode; and   an electrolyte.   
     
     
         20 . The secondary battery according to  claim 19 , wherein the electrolyte is positioned in a hole in the polymer porous film. 
     
     
         21 . A method for manufacturing a separator, comprising:
 a first step of mixing a ceramic-based material comprising a metal oxide microparticle and a first solvent to form a first mixture;   a second step of mixing the first mixture, a first binder, and a second solvent to form a second mixture;   a third step of mixing the second mixture, a second binder, and a third solvent to form a third mixture;   a fourth step of applying the third mixture onto a polymer porous film; and   a fifth step of heating the polymer porous film coated with the third mixture at higher than or equal to 60° C. and lower than or equal to 300° C. to be dried.   
     
     
         22 . The method for manufacturing the separator according to  claims 21 ,
 wherein the polymer porous film coated with the third mixture is heated at higher than or equal to 60° C. and lower than or equal to 200° C. to be dried in the fifth step.